Noelia mahaniae

Set number: 2608

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10µm

Noelia mahaniae, Late Paleocene, DSDP Leg 39, Sites 354, Ceará Rise, North Atlantic Ocean

Holotype in the mobile mount

Final Epithet

Noelia mahaniae Varol, 2023

Basionym

Noelia mahaniae Varol, 2023

Diagnosis

A large (9.0–12.0 μm) subcircular species of Noelia with a non-birefringent distal shield, an appressed proximal shield and an elliptical tube cycle that protrudes distally.

Etymology

In honour of nannofossil specialist Mrs Mahani Mohamed, retired nannofossil taxonomist and biostratigrapher from Petronas, Kuala Lumpur, Malaysia.

Dimensions Of Holotype

Length/Diameter of the distal shield: 10.82 μm (measured in side view in phase-contrast), the width/diameter of the proximal shield: 10.10 μm (measured in plan view in the bright field), the maximum length/diameter of the tube cycle: 7.27 μm (measured in side view in phase-contrast), the maximum height of the distal shield and tube cycle: 4.60 μm (measured in side view in phase-contrast), the free length of the tube cycle: 1.25 μm (measured at side view in phase-contrast).

Description

The distal shield is lenticular in shape, having a shallow depression at the proximal end of the tube cycle occupied by the appressed proximal shield. The combination of the tube cycle and the appressed proximal shield resembles an asymmetrical X-shape in side view. The number of segments that construct the shield is typically between 30 and 50.

Optical Properties

In cross-polarised light, with the gypsum plate inserted, when the length of the species is aligned north-south direction, the tube cycle shows the blue sectors aligned to the horizontal axis on the distal side. In contrast, the blue sectors align with the vertical axis on the proximal side (Plate 10, Fig. 10 in Varol, 2023). The entire species appears birefringent in side view.

Remarks

Noelia mahaniae is easily distinguished from other species of Noelia by having subcircular shields and an elliptical tube cycle.

References

Varol, O. 2023. New paleocene calcareous nannofossils: Carlamuelleria, Davidbukrya, Mauriceblackia, Noelia and Senelia. Marine Micropaleontology. 180: 1-41.